1. Field of the Invention
The present invention relates to an electric working machine, such as an electric lawn mower, and particularly, to an improvement in an interlock system in an electric working machine including a switch capable of being switched between a first state in which it is possible to supply electric power from a battery to an electric motor and a second state in which it is impossible to supply the electric power from the battery to the electric motor. A key member is capable of being inserted into the switch only in the second state, to switch the switch, and a connector is provided for connecting an external power source for charging the battery. The improvement is that when the switch is in the state in which it permits the supplying of the electric power from the battery to the electric motor, the charging of the battery is impossible.
2. Description of the Prior Art
An interlock system in an electric working machine is already known, for example, from Japanese Patent Application Laid-Open No. 4-229515 and U.S. Pat. No. 5,301,494 and the like.
In the interlock system in the above Japanese Patent Application Laid-Open No. 4-229515, however, the switch is brought into the first state by insertion of the key member, so that the connector is covered with the key member, thereby making the charging of the battery from the external power source impossible. By removing the key member, the switch is brought into the second state, and it is possible to connect the external power source to the connector. Therefore, the interlock system is a complicated structure, and the insertion and removal of the key member is required to switch the switch. This results in a troublesome switching operation. In the interlock system in the U.S. Pat. No. 5,301,494, a slide plate is required which is movable between a position in which it is possible to connect the external power source to the connector, and it is impossible to insert the key member into the switch, and a position in which it is impossible to connect the external power source to the connector, and it is possible to insert the key member into the switch. This results in an increased number of parts.